Figure 6.

Bioinformatical and structural analysis indicates giant panda transferrin receptor (TfR) as a putative receptor for pFPV-sc. (A) Giant panda TfR is akin to the feline TfR at the virus-binding motif. Multiple sequence alignment indicated that the majorities of the crucial amino acid residues that forms the virus binding motif (βI-1, βII-1, βII-2, βII-3, βI-6, βII-7 and βII-8 loops) are conserved between feline and giant panda TfRs. Differences between giant panda TfR and feline TfR are marked red. (B) TfR topology are relatively conserved between different host species, with the virus binding motif well exposed. Side view of the dimeric human TfR (PDB accession number: 7ZQS), feline TfR and giant panda TfR (modelled using homology modelling) are shown in surface representation and colored by one monomer gray, and another monomer blue. Virus binding motifs of feline and giant panda TfRs, specified in (A), were depicted in red in the gray-colored monomer.